Which element among the following forms $P \pi-P \pi$ multiple bonds?

Which of the following reactions is incorrect?

The bond energies (in $kJ \ mol^{-1}$) of $P-H$,$As-H$,and $N-H$ are respectively:

The compound$(s)$ which generate$(s)$ $N_2$ gas upon thermal decomposition below $300^{\circ} C$ is (are)
$A. NH_4NO_3$
$B. (NH_4)_2Cr_2O_7$
$C. Ba(N_3)_2$
$D. Mg_3N_2$

Which among the following group $15$ elements does not exhibit allotropy?

Nitric acid oxidises phosphorus to